It's possible to make one's own grape pest disease culture by looking for sick or dead caterpillars. If sick, they will lose color and move slowly, if at all. At death, they often hang limp and darkened from a leaf by a spot of "glue." Several of these are all you need to treat an acre of vines. Whiz them in a blender with a quart of water, strain, and dilute to spray your vines. Use right away, as this mixture will start to putrefy after just twelve hours. It's a bit grisly, but very cheap and very effective. Just don't forget to clean the blender
